Multi-path interference performance testing

Abstract

A system comprises a laser configured to produce a laser beam and to be optically coupled to a first end of an optical fiber of a device under test, a phase mask configured to selectively pass one of a plurality of modes and to be optically coupled to a second end of the optical fiber of the device under test, and a detector optically coupled to the phase mask and configured to determine an intensity of the beam received over the optical connection from the phase mask. The system may further comprise a data analyzer connected to the detector and in selective communication with the phase mask, wherein the data analyzer is configured to set the phase mask to selectively pass a fundamental mode, set the phase mask to selectively pass a higher order mode, receive intensity data from the detector, and determine a performance in the form of at least one performance factor for said device under test according to said intensity data.

1. A system, comprising:
 a laser configured to produce a laser beam and to be optically coupled to a first end of an optical fiber of a device under test; 
 a phase mask configured to selectively pass one of a plurality of modes and to be optically coupled to a second end of said optical fiber of said device under test; 
 a detector optically coupled to said phase mask and configured to determine an intensity of said beam received over said optical connection from said phase mask; and 
 a data analyzer connected to said detector and in selective communication with said phase mask, wherein said data analyzer is configured to:
 set said phase mask to selectively pass a fundamental mode, 
 set said phase mask to selectively pass a higher order mode, 
 receive intensity data from said detector, 
 perform an analysis on said received intensity data, 
 determine an analysis result indicative of an undesired mode being passed by said phase mask in addition to said mode said phase mask is set to selectively pass, 
 send a directive to said phase mask to adjust settings of said phase mask to minimize said analysis result indicative of said undesired mode, and 
 determine a performance in the form of at least one performance factor for said device under test according to said intensity data. 
 
 
     
     
       2. The system of  claim 1 , wherein said performance factor is a signal-to-noise ratio. 
     
     
       3. The system of  claim 1 , further comprising a data collector connected to said data analyzer and configured to store and retrieve data received from said data analyzer. 
     
     
       4. The system of  claim 1 , further comprising a polarization controller optically coupled between said laser and said device under test, whereby said polarization controller is configured to isolate one of two orthogonal components of said beam. 
     
     
       5. The system of  claim 4 , wherein said polarization controller is further configured to deterministically create a state of polarization specified by said data analyzer. 
     
     
       6. The system of  claim 4 , further comprising a second polarization controller optically coupled between said device under test and said detector, wherein said second polarization controller is configured to readjust said beam optically received from said device under test. 
     
     
       7. The system of  claim 1 , wherein said analysis includes performing a fast-Fourier transform analysis of said received intensity data, and wherein said analysis result includes a resonance frequency peak indicative of said undesired mode being passed by said phase mask. 
     
     
       8. The system of  claim 1 , wherein said mode said phase mask is set to selectively pass is said higher order mode, and said undesired mode is said fundamental mode. 
     
     
       9. The system of  claim 1 , wherein said mode said phase mask is set to selectively pass is said fundamental mode, and said undesired mode is a higher order mode. 
     
     
       10. The system of  claim 1 , wherein said laser is configured to allow for adjustment of the wavelength of the laser beam, and wherein said data analyzer is further configured to adjust said laser to produce a laser beam of a predetermined frequency. 
     
     
       11. A method, comprising:
 setting a phase mask to selectively pass a fundamental mode of a laser beam from a laser and exiting a device under test; 
 receiving intensity data from a detector regarding the fundamental mode; 
 setting the phase mask to selectively pass a higher order mode of the laser beam exiting the device under test; 
 receiving intensity data from the detector regarding the higher order mode; 
 performing an analysis on the received intensity data; 
 determining an analysis result indicative of an undesired mode being passed by the phase mask in addition to the mode the phase mask is set to selectively pass; and 
 sending a directive to the phase mask to adjust settings of the phase mask to minimize the analysis result indicative of the undesired mode; and 
 determining at least one performance factor for the device under test according to the received intensity data. 
 
     
     
       12. The method of  claim 11 , wherein the performance factor is a signal-to-noise ratio. 
     
     
       13. The method of  claim 11 , further comprising setting the laser to produce a laser beam of a predetermined frequency. 
     
     
       14. The method of  claim 11 , further comprising:
 setting the phase mask to selectively pass a second higher order mode of the laser beam exiting the device under test; and 
 receiving intensity data from the detector regarding the second higher order mode. 
 
     
     
       15. A non-transitory computer-readable medium tangibly embodying computer-executable instructions comprising:
 setting a phase mask to selectively pass a fundamental mode of a laser beam from a laser and exiting a device under test; 
 receiving intensity data from a detector regarding the fundamental mode; 
 setting the phase mask to selectively pass a higher order mode of the laser beam exiting the device under test; 
 receiving intensity data from the detector regarding the higher order mode; 
 performing an analysis on the received intensity data; 
 determining an analysis result indicative of an undesired mode being passed by the phase mask in addition to the mode the phase mask is set to selectively pass; and 
 sending a directive to the phase mask to adjust settings of the phase mask to minimize the undesired mode; and 
 determining at least one performance factor for the device under test according to the received intensity data. 
 
     
     
       16. The computer-readable medium of  claim 15 , wherein the performance factor is a signal-to-noise ratio. 
     
     
       17. The computer-readable medium of  claim 15 , further comprising setting the laser to produce a laser beam of a predetermined frequency. 
     
     
       18. The computer-readable medium of  claim 15 , further comprising:
 setting the phase mask to selectively pass a second higher order mode of the laser beam exiting the device under test; and 
 receiving intensity data from the detector regarding the second higher order mode. 
 
     
     
       19. The computer-readable medium of  claim 15 , wherein the mode said phase mask is set to selectively pass is the higher order mode, and the undesired mode is the fundamental mode. 
     
     
       20. The computer-readable medium of  claim 15 , wherein the mode said phase mask is set to selectively pass is the fundamental mode, and the undesired mode is a higher order mode.